Process for producing long continuous electric arcs.



0. SCHCNHERR & J. HESSBERGER.

PROCESS FOR PRODUCING LONG CONTINUOUS ELECTRIC ARCS.

APPLICATION FILED 0GT.17. 1912.

1,095,426, Patented May 5, 1914.

L F g I 1 f I xi J2 N T I i UNITED STATES PATENT OFFICE- OTTO SCHONHERR, 0F DRESDEN-STRIESEN, GERMANY, AND J'OHANNES HESSBERGER,

OF GHRISTIANSAND, NORWAY, ASSIGNORS T0 NORSK HYDRO-ELEKTRISK KVAEL- STOFAKTIESELSKAB, OFOHRISTIANIA, NORWAY, A CORPORATION OF NORWAY.

PROCESS FOR PRODUCING LONG CONTINUOUS ,ELECTRIO ARCS.

Specification of Letters Patent.

Patented May 5, 1914.

Original application filed May 18, 1910, Serial No. 562,097. Divided and this application filed October 17,

912. Serial No. 726,369.

To all whom it may concern:

Be it known that 'we, O'r'ro SQHONHERR and JOHANNES HESSBERGER, subjectsof the King of Saxony and'the King of Prussia, respectively, residing, respectively, at Dresden-Striesen, Germany, and Christiansand, Norway, have invented new and useful Improvements in Processes for Producing Long Continuous Electric Arcs, of which the following is a specification. This application was origin'allyfiled May 18th, 1910, Serial No. 562,097, the present s ecification and claims being a division of t e same ursuant to the requirement of the Patent Oi ce.

In the specification of Letters Patent No. 930238 we have described the production of long stable electric arcs by causing an arc to spring from an insulated electrode connected with one pole of a source of electricity and situated at, or toward, oneend of a long tube, or passage, the tube, or pa-ssage, itself being elther connected with the other pole of the source of electricit or containing at, or toward, the other en thereof,

a second electrode connected-with theother pole of the source of electricity, while at the same time a current-of air, or other gas, or gases, is passed through the tube, or passage, with .such velocity that a long and steadily burning electric arc is produced and maintained within the said tube, or passage. The said specification discloses, for .the first time, a new principle, namely surrounding a long electric arc with a layer of non-conducting fluid and maintaining this layer offiuid in such a condition that it is easier for the arc to continue in the position in which it is burning than for it to s ring through the layer of surrounding uid. In order to bring about this condition, it is necessary that the layer of gas,

(which we will hereinafter, for brevity, refer to as air, although other gas, under which term we include a gaseous mixture,

may be used in carrying out this invention) should not be allowed to become so hot that it is capable of conducting electricity, or at all events that it should not reach this high temperature until it arrives at a point in the tube, or passage (which we will hereinafter, for brevity, refer to as the tube), where 1t is desired that the arc should pass through the layer to the second electrode orin which the arc is produced, commencing at a point either below, or at a short distance above, the insulated electrode. It is also preferable, according to the said specification, that the air should be passed into the tube. with a tangential or rotary, motion.

The specification of Letters Patent No. 976,002, describes the production of stable electric arcs by means of two tubes, each rovided with an insulated electrode and eadl-ng lnto a common space. Air is blown past each electrode into the respective tube and is led away from the common space, ,whlle the arcs produced may join in the common space and form one continuous arc. In Figure 3 of the drawings accompanying the last-named specification the two tubes are shown parallel to one another, butt-he specificat1on does not restrict the arrangement to this particular position, as the two tubes may be placed end on to one another 'so that one stralght contlnuous arc is obtained between two Insulated electrodes, air being blown past each electrode and being withdrawn from the tube at, or near, the mid part thereof. We havediscovered that insteadof the air passing through the tube as described in the said specification, the arc can also be produced and maintained with certain advantages-if the air be made to pass through the tube or through diiferent portions of the tube in different directions lengthwise of the tube at one and the same time as hereinafter explained. For instance the air can be passed along the wall inside the tube in one direction and then back again in the reverse direction immediately sur rounding the are, so that it asses through the saidtube or through different portions thereof, side by side, in different directions lengthwise of the said tube at one and the same time, or the air can be caused to pass 1 entrance and exit being at the larger end of in two opposite directions along different portions of the are, being iutroducedfor ini stance into the tube at a point between the two ends thereof, and the gases bcin removed from the tube at, or near, the two ends thereof simultaneously, preferably being withdrawn through each electrode, or through the parts of the apparatus which act as electrodes, or these variations can be combined so that air is introduced into the tube at each of the two ends thereof and passes alon the interior wall toward the mid part an then reverses its course so as to pass back along the arc toward each of the two ends of the tube again.

When carrying-out'this invention we prefer to impart to the air, or to part of the air, entering the tube a tangential, or rotary, motion, for instance such as 1s described in the aforesaid specification of Letters Patent No. 930,238, and it is also generally advisable to cool the openings throu h which the hot gases are removed from t e tube. The tubes which can be used in carrying out .this invention may be variously shaped, for instance the tube contamlng the arc can be a long cylinder, or a' short tube, or passage, of a diameter greater than its length, or it can consist of two cone-shaped tubes with their larger ends abutting against each other. This latter shape is more particularly useful'when the gases-are taken away from each end of the tube. We prefer generally to surround the tube containing the electric arc with a second tube and to pass the air through the space between the two tubes before a lowing it to enter the inner tube, so that in this way the temperature of the inner tube is lowered and the air becomes preheated before entering the inner tube and consequently a higher temperature of the arc is admissible within the inner tube than would be the case if no such preheating took place. When, according to this invention, the air passes along the interior wall of the tube and then back a ain immediately surrounding the arc, a fart er advantage is attained, because heat is able to pass directly from the air immediately surrounding the arc to that which is moving in the opposite direction alon the interior wall of the tube, and the trans erence of heat is greater because there is no intermediate wall through which the heat has to pass and since the hottest air does not come into contact with the wall of the tube a much higher temperature of the arc can be employed within the tube than would be the case if the temperature of the arc had to be restricted to revent the material of which the tube is ma e from beingzviiljured.

en the air is led into the tube at one end only and the gases are removed at the i same end, the tube can be cone-shaped the eacli of the cone.

If desired, instead of introducing the 5 whole supply of air into the tube in the manner hereinbefore described, it can be introduced partly in such manner and partly in any other suitable way, for instance as described in the specification of the aforesaid Letters Patent No. 930,238.

l The electrodes employed in carrying out I the process according to this invention can be of various shapes. For instance they can be rod-shaped, as described in the aforesaid specification of Letters Patent No. 930,238, or they can be formed like a ring, and the end of the arc can continually move around the ring.

'We give the following ways as examples of how this invention can be performed in practice, referring to the accompanying drawings, but the invention is not limited to these examples.

In the drawings, Figs. 1 and 2 represent vertical sections of apparatus suitable for use according to this invention, showing how the electric arc can be produced and how the gas is caused to pass in the desired direction or directions,

Fig. 1 illustrates an arrangement in w ich the gas is caused to pass in two opposite directions along different portions of'the tube R the gas being introduced at E at the mid part 0 the length of the tube and the-gases being removed from the tube at the ends thereof simultaneously through the electrodes P and P 4 As indicated in Fig. l the tube R can be surrounded by a conduit S and the air can be passed by means of a ipe A through the openings E into the tu ,e B. As shown in Fig. 2'the upper electrode can be cooled by means of a Water jacket after the manner of a Liebigs condenser. The portion of the air passmg directly through the upper tube P mixes with the heated gases leavin the lower tube P and tends to cool them down quickly, and this is of advantage when the electric arcs are used for carrying out chdothermic reactions in gases, for instance for the production of nitric oxid.

In both the figures L'represents insulating material.

What we claim is:

1. The process of roducing a long stable electric arc in a tu e or passage provided with an insulated electrode by causing a gas to pass into the space surrounding the are at various places near the mid part of the length of the said tube or passage and to pass out from the said tube or'passage near each of the ends of the arc whlch are situated at or near each end of the tube or passage substantially as hereinbefore explained.

2. The process of producing a long stable electric arc in a tube or passage provided with an insulated electrode by causing a gas to pass into the space surrounding the are or passage at one or more than one place at or near the mid part of the length of the said tube or passage and to pass out from the said tube or passage near each of the ends of the are which are situated at or near each end of the tube or passage and causing the air to leave the tube through the electrode outlets while cooling the said gases on leaving'the arc space, substantially as hereinbefore explained.

In testimony whereof we have hereunto set our hands in the scribing Witnesses.

Witnesses as to the signature of Otto Schtinherr:

PAUL ARnAs, ARTHUR GUBE. Witnesses as to the signature of Johannes Hessberger:

P. BIRKELAND, T. Vnsrmr.

presence of two sub 

